BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

I rode a single spark engine r1150r today. It was alot smoother with less vibration than the twin spark motor I have. Is that normal? I have only had my 04 r1150r for a couple of weeks now.

I had the older R1100R and now ride a R1150R twin spark. Both bikes were great but could show their own range vibrations in different degrees. I found this more to be with their current state of tune and not so much the different motors. How long ago was the twin spark tuned? If you don't have records or its been awhile, give it a TB sync and check the plugs/gaps. If it stays, check other areas that can cause vibration...play in the steering head, out of balance/worn tires, warped disc, or bent rim. I think the bikes should run about the same given all other things equal.

Roxster

The greatest influence on engine vibration is the TB's out of balance, especially in the 3000 rpm to 4000 rpm range where the engine spends most of its time. Remember we have reciprocating cylinders which should be generating the same effort, if not ,one leads and the other follows creating undue vibrations.

The second influence would be a weak or bad costick coil, as they mount directly on the plugs and fail as a result of excessive heat.

Both easily solved, the second one will cost a few $$$$

Good luck and share what you find.

Roxster wrote:I had the older R1100R and now ride a R1150R twin spark. Both bikes were great but could show their own range vibrations in different degrees. I found this more to be with their current state of tune and not so much the different motors. How long ago was the twin spark tuned? If you don't have records or its been awhile, give it a TB sync and check the plugs/gaps. If it stays, check other areas that can cause vibration...play in the steering head, out of balance/worn tires, warped disc, or bent rim. I think the bikes should run about the same given all other things equal.

Roxster

Can you actually gap the plugs? Last I looked, they had twin concave leads that more or less surrounded the electrode.

TB's are sync'ed. I had those checked. I hope its something simple thats causing all the vibes.

SpeedwayRN

I don't want to belittle your reply, but the folowing statement bothers me

I had those checked

My question is: What is your level of confidence on the person that checked the TB sync? There are some Techs out there that would not be qualified to chmge a light bulb......just my 2 cents.

If the bike's TB's are sync'd correctly, both mirrors should be equally clear.

I agree--TB sync is the key. A really good BMW mechanic is hard to find as well. Many are young (no slight on age either---but with time comes experience and knowledge) (most of the time)

On the twin ground plugs----I'm not at all convinced they are the way to go. The spark will always follow the path of least electrical resistance----it only fires to one ground---not both. They are able to be gapped but you have to use the style of gapping tool that uses wires of varying thickness instead of the standard style of gage. If one side is closer to the center electrode by .001 or less it will fire to that side and ignore the other side. I really don't see the advantage of the more expensive plugs. It just empties your wallet faster.

Wayne